This invention relates to an oxygen regulator for use in an aircraft.
Currently available demand oxygen regulators such as that disclosed in U.S. Pat. No. 3,509,895 supply a recipient with a mixture of breathable fluid which is directly proportional to the altitude at which the aircraft is flying. However, each individual's physiological response to various stresses encountered during a flight is different. Depending upon the individual, during periods of increased work levels, an increase in the percentage of the oxygen in the breathable fluid may be needed to stabilize minute ventilation of blood gases. If the percentage of oxygen is not increased, the recipient's body responds by automatically increasing his inhalation-exhalation rate and/or tidal volume in order that the waste products produced by the body may be eliminated by bringing more oxygen into the lungs. However, under such conditions, hyperventilation can occur since the efficiency of respiration is decreased due to an increase in the work of breathing.
In addition, during periods of inactivity the percentage of oxygen in the breathable fluid needed to stabilize minute ventilation of blood gases in an individual recipient may be less than that supplied by the altitude responsive regulator. If the percentage of oxygen is not reduced, the recipient may experience hyperoxia.